Mounting of boilers of mallet locomotives



April 23, 1940. K RTHLER 2,197,831

MOUNTING OF BOILERS 0F -MALLET LOCOMOTIVES I Filed June 25, 1938 3 Sheets-Sheet 1 /n van for MMM@ By' ffeal.

A//omey April 23, 1940. K. RTHLER 2,197,831

MOUNTING 0F BOILERS OF MALLET LOCOMOTIVES Filed June 25. 1938 3 Sheets-Sheet 2 Inventor El. 5 ,i H w 'g feax.

A Homey April 23, 1940. K. RTHLER 4 2,197,831

MOUNTING 0F BOILERS 0F MALLET LOCOMOTIVES Filed June 25, 1958 5 Sheets-Sheet 3 g /FE/QLE Afiornev Patented Apr. 23, 194()y MOUNTING oF BloILERs oF LoooMoTIvEs MALLET Karl Rthler, Kassel, Germany, assignor .to

Henschel & Sohn, Gesellschaft Vmit beschrnkter Haftung', Kassel, Germany Application June 25, 1938, Serial No. 215,865 In Germany June 26, 1937 f 7 Claims. (C1. 105,-1'117)l The present invention relates to an improved mounting of the boiler of a Mallet locomotive. In connectionwith' Mallet locomotives, it is necv essary to provide on each side of the locomotive two)or Imore independent groups of springs in in which the springs areconnected by compensating levers, each'group of springsA with' ,compensating levers `forming a complete unit. In most constructions 'of the Mallet locomotive, the lboiler is supportedupon the front bogie by means of one or two plane Atable supports and consequently the iront and the rear truck or frames are 'al-- ways guided parallel to one another.l Lateral displacement of the plane supports must in this construction be avoided. The front bogie and the'rear frames of the locomotive cannot in this construction adapt themselves independently to an uneven*y track, and unevenness of the track must be taken up by variations in the elongations of the various groups of springs,these variations being substantially equal to thevariations which would occur if all the groups of axles were mounted in a common frame.

With-a very long wheel base of a Mallet locomotive having aconsiderable numberof driven wheels and with sharp curves in the line of the track, veryk considerable relative inclinations oi the axles of the front bogie with regard tothe axles of the rearvframe will occur, apart from inclinations due to accidental unevenness of the track. These relative inclinations lead to very considerable over-loading or under-loading of the Springs and the wheels at one or the ,other` side of the locomotivesyand have to be taken care of by special devices.

Another very disturbingvinflue'nce is the fact that on passing sharp curves of the track the front part of the boiler will move very considerably laterally with' regard to its front bogie, which again influences in avery unfavourable manner the distribution of the load vupon the spring groups at the left and at the right side olf-the locomotive,` either the one or the other grou becoming overloaded. I

These two main inuences and the influence of the unevenness rof the track frequently have a cumulativeelfect and they produce very considerable variations in the individual spring and wheel loads, which` may lead to derailment'of the locomotive and fracture of springs.

Inview of the above-mentioned unfavourable influences, it is advisable to aim in connection with a Mallet locomotive having a very long wheel base, at the obtention of a three-.point support. Ini order to obtain ,such a support,- n .connection at .the left hand side will be over-.stressed and ,5v

with a VMallet locomotive, it is important to support the front part `of the boiler by means of a spherical or ball vbearing in the middle plane of the frame of the vfront v.bogie and to arrange for w al1 the driven and running axles of the rear lframe C to be connected on either side by a left hand and a right hand group'of springs, the springs of each group being connected by compensating levers. Independently oi this arrangement the 'iront bogie must again have a three-point sups port, for instance by connecting'theleading running axles and the rst driven axles by means of longitudinal and transverse levers and by two lateral groups of springs ofthe following three driven axles. rCurves in the track and accidental unevenness will then not lead to any substantial variation of the spring tension and. the wheel loads. There will, however, still remain the unfavourable inuence ofthe lateral displacement of' the front part of the boiler with regard to its bogie occurring in curved portions of the track, and it is necessary to compensate or avoid the effect of this lateral displacement upon the load v'known manners of mounting-the vboiler upon the front bogie, and Fig. 5 showing diagrammatically the improved manner vaccording to the present invention.

Referring first to Fig. 3, it will'be seen that the vboiler 2 is provided upon its under side with' a Asemispherical pivot I which rests in a cor- Vrespondingly, shaped socket 3. The socket 3 `is slidable upon a'horizontal surface il of the yiront bogie 5. Assuming the maximum displacement of the socket 3 to be indicated bythe distance 6 and the portion of the weight ofthe boiler trans- :45 mitted by the pivot I to Vbe indicated by theletter W, then it will be seen that at the maximum lat-` eral displacement of the boilerfwith regard to the front bogie, the weight'W will no longer be `distributed uniformly upon the .wheels at the left hand side and those-at the rightfhand side, but ywill be taken up chiefly by those atthe left hand side. Consequently'the :springs interposed ,between the 4wheels and the frame of the bogie those at the right hand side will be under-stressed, whilst the distribution of the load upon the axles of the rear frame will remain unaltered. The turning moment MOM increasing the stressing at the outer side of the curve in the track will be represented by M OM =W 6.

In the construction shown in Fig. y4,l the positions of the semispherical pivot andthe sldable socket are reversed, the pivot I being fixed to the horizontal surface 4 of the bogie frame 5 and the boiler 2 being provided upon its under surface with a xed support 8 having a horizontal surface 9 which slides upon the top of the socket 3 co-operating with the semispherical pivot I. In this construction the weight WI of the front part of the boiler taken up by the front bogie will always act in the middle plane of the front bogie and therefore, even when the front part of the boiler is displaced with regard to the front bogie by the maximum distance 6, the load will be distributed equally upon the left hand and right hand side springs and wheels. On the other hand, there will be a turning moment which tends to turn the front part of the boiler to the outer side of the track. This turning moment is taken up by the springs of the rear frame, the outer springs and wheels of the rear frame being over-stressed and the inner springs and wheels being under-stressed.

To avoid the disadvantages of the construction diagrammatically illustrated in Figs. 3 and 4, the invention provides a construction diagrammatically indicated in Fig. 5. v

In this construction, both the boiler 2 and the frame 5 of the front bogie are provided with substantially horizontal slide surfaces 9 and 4 respectively and between these surfaces there is slidably mounted a ball joint consisting of a spherical pin I and a corresponding socket 3. The movement of the ball joint I', 3 relatively to the horizontal guideways 9 and it is controlled by a double-armed lever I0, I2, pivotally mounted at II upon the socket 3. vThe upper end of the lever arm I0 is vertically guided by means of a slide I3 in a guideway I4 of theV boiler support 9, whilst the lower end of the lever arm I2 is ver- ,.tically guided by means of a slide block I5 in a vertical guideway I6 of the bogie frame 5.l The `effective arms of the lever I0, I2 are preferably so chosen that upon lateral displacement of the boiler with regard to the front bogie, the distances of the middle planeY of the ball joint from the middle plane of the bogie and the middle plane of the boiler will be about equal. Therefore, the maximum displacement of the boiler will be equal to sI-l-s2 and the disturbing moments due to the displacement will be about halved, the moment MOMI being equal to W sI and the moment MOM2 being equal to W s2. These moments are taken up by the springs of the front frame and by the springs of the rear bogie respectively.

It will thus be seen that by the improved ar- -rangement there will be reduced over-stressing or overloading at the outer side of the curve and also reduced under-stressing at the inner side of the curve as compared with those occurring in the construction indicated in Figs. 3 and 4.

Assuming the load of the boiler taken up by the front bogie to be say 23,500 kg. calculations and tests have shown that in the construction laccording to Fig. 3 there -will be over-stressing of the wheels Vamounting to about 28% and overstressing of the springs amounting to about 52%. With the same load and in the case of the construction sho-wn in Fig. 4, the over-stressing and under-stressing respectively of the wheels of the rear frame will amount to about 16% and overstressing and under-stressing respectively of the springs will amount to 22%.

In the construction according to theinvention shown in Fig. 5 there Will be stress variations .both in the front bogie and in the rear frame, and

those in the front bogie will amount to about 15.3% as regards the wheels and about 28.4% of the springs. In the rear frame, stress variation of the Wheels will be 7.3% and that of the springs 10%. Itwill thus be seen that by the improved constructions, the stress variations are maintained within permissible limits and will avoid any possibility of accidents when passing over sharp curves. l

Another feature of the invention consists in providing veryjsimple means .for returningv automatically the boiler to its normal positionwhen the locomotive has'passed a curve. -This is, according tothe invention, attained by suitably shaping the surface upon which the'ball joint slides upon the front bogie.l f f A constructional example of the invention is indicated in the drawings in Figs. 1, 2 and 6. Y

Referring rst toiFig. 6, a indicates the* boiler which is in manner known perse supported upon a front bogie' b' and a rear frame 5i, lwhich `are coupled together as-'usual by a vrod-X. The front bogie has four driven wheel pairsl driven `by an engine k and a runningwheel pair rm whichis not driven, whilst the rear frame has four driven wheel pairs Z and two pairs of non-driven vrunning wheels m. The spring suspension of the front `bogie is indicated by the letters an and o whilst the spring suspension ofthe rear frame is indicated by the letter p. 4In .both the bogie `and the frame the individual'sp'rings' are connected by levers to form a complete :unit on either side of the frame. The boiler tv rests upon the rear bogiei at threepoints A, B,B, the point A being vin the middle plane of the boiler` and the points B being on either side of the middle plane.,The front part of th-i-boler rest'sfat Cupon thefront bogie, this support being the subject lof lthe invention` andshown in details in Figs. 1, 2l and 5. Referring to Figs. 1 and 2 which show in detail the front support of-the boilerfagindicates the boiler and b the vframe ofthe front ybogie. ,To the under side ofthe boiler is Xed a support c havf` ing a plane under surface.,n'I'he bogiemfrane Ab is provided with an upper surfaced, and between the under surfaceof the supporto and thesurface vdy of the bogie there isuslidably mounted a ball joint consisting of anrupperlpivoted member e having a semispherlcal bearing surfaceresting in a corresponding semispherical `s urvfacewof a socket member-f. To the socket member' ye are pivoted at intermediate pointsQ and Qf armed leversg and h respectively which in the normal position of the boiler are locatedin the Amidaie plane of-the boiler andthe bogie., 'The upper end of each lever is forke d,qthe,forked portions being pivotally connected at Pto blocks slidably mounted in vertical guid'e'w'ays formedin the boiler support c.Y The lower vends of 'the'levers are also pivotally vconnecte'd'at Rin any suitable manner to similar' blocks slidably mounted in vertical guideways'forme'd inthe bogie frame b. The positions of the-pivots of thev levers andthe lengths of the arms 'are socho'sen that during lateral- 'displacement' of f the boilerl with regard to rur ` ner asto-obtaina .d iierentproportionbetween Sii ` movement of the parts.

.the said distances.

- In atrack curve, the direction of .,tli e longitudinal middleaxis of the frontybogie is displaced withrespect to that of theboilerpthetwo@ axes vformi,ng-an` angle between them. Now, itis ,obj-

' ,vicusythatthe further @particularpoint 0n cnc axisnorflimby of the displacement, angle iszjfrqni vits distance from apointon the othervv lirnbpr axis located at an equalgdistance from. the said .apex pointA The levers `gand It the front bogie and the boiler. Consequently,

whenxthe-fvehcle Atraverses a curve,.each leverv is displaced to a different extent. The lever h located closer to the apex point has a shorter path and thus the smaller displacement,whil st the lever g, located further forwardly of the Vehicle, undergoes the greaterv displacement.. On the other hand, however, the intermediate pivot points Q and Q",of the levers g and h, should,

yon account ofthe parallel guiding of the ball.

joint, constantly carry out displacements of equal.

sizes. The axes of rotation of the levers g and h always lie parallel to the axis of the front bogie b. In'order, therefore, that the ball socket f shall be guided parallel to itself and to the centre of the bogie b, different lever transmissions are necessary. As can be seen from Figure 1, this is'A achieved in the example described, by making`-the two levers g and h of the same overall length, but locating the intermediate points Q' and Q" in such positions therealong that the proportion of the lengths of the arms PQ'; QR and PQ; QR are different. In order to'provide for automatic return of the parts c, e, f, d into the initial position after the `train has passed over a curve in the track, the bearing surfaces ,of the socket f 'are made wedge shaped. This construction is extremely compact, which is a very considerable advantage in view'of the'small available space. u

It will be understood that other means may be' provided vfor positively controlling the relative For instance, instead of guiding the upper ends of the levers in vertical guideways, links might be used, and the levers might, for instance, be replaced by toothed racks and wheels.

I claim: Y

1. In a Mallet locomotive of the type wherein the boiler is supported upon a front'bogie and a rear frame the combination of: a boiler; a iront bogie; means for supporting said .boiler on said front bogie, said means comprising a guideway xed to the under side of the boiler; a guideway uponthe bogie; and a balll joint located between said two guideways; said ball-joint comprising a socket member slidable upon one of said guideways and a ball, in said socket, and slidable upon the other guidewaypand means for controlling the movement of said ball joint due to lateral displacement ofthe boiler with regard `are located at d iierentv distances, from the apex of the angle'` formed by the relative displacement of the middle-axes ojf 2. In aMallet locomotive. of the type wherein the boilcreis supported upon-,a ,iront bogie and arear; frame, the combination of; a boiler al front bogie; a. gllideway. `iixed tothe under side of' the boiler; ,a guideway upon the bogie; a ball joint slidable between said two guideways;-and-means for controlling themovementof i said ball joint due to lateral displacement of the .boilerwith regard to ythcbogie to maintain a definite proportion between thedistancesiof said ball joint from vthe middle plane ofthe boiler and the bogie, said ball joint comprising a semispherical socket member and a semispherical pivot member, said socket member `being slidable uponthe guideway upon the bogieand said pivot member. being slidable upon the vguideway iixed to the boiler 3. In la Malletk locomotive of the ,type wherein the boiler is ,supported upona front bogie and a rear frame, the combination of: a boiler; a front bogie; means forsupporting said boiler on said front, bogie, said means comprising..a pguideway fixed to the under side ,of the boiler; -aguideway upon the bogie; and a ball jointlocated .between `said two guideways; saidpballfjoint.comprising a socket member slidable upon one of said guideways and a ball', in said socket, and slidable upon the other guideway; 'and' means for controlling the movement-of said ball joint due to lateral displacement of the boiler with regard to the bogie to maintain a definite proportion between the distances of said ball joint from the middle plane of the boiler and the bogie, said guideway upon the bogie rising laterally from its centre to its ends.

4. In a Mallet locomotive of the type wherein the boiler is supported upon a front bogie and a rear frame, the combination of: a boiler; a front bogie; means for supporting said boiler on said front bogie, -said means comprising a guideway fixed to the under side of the boiler; a guideway upon the bogie; and a ball joint located between saidtwo guideways; said ball-joint comprising a socket member slidable upon one of said guideways and a ball, in said socket, and slidable upon the other guideway; and means for controlling the movement of said ball joint due to lateral displacement of the boiler with regard to the bogie to maintain a denite proportion between the distances of said ball joint from the middle plane of the boiler and the bogie, said means for controlling the movement of the ball joint comy prising leverseach pivoted at an intermediate pointalong the length thereof to the ball joint and operatively connected at the ends thereof to the boiler and the bogie respectively.

5. In a Mallet locomotive of the type wherein the boiler is supported upon a front bogie and a rear frame the combination of: a boiler; a front of the boiler and the bogie, said controlling means comprising levers each pivoted at an intermediate point along the length thereof to the ball 7,5

joint; vertical gi'xideways for theends of said levers provided uporthe boiler andthe'bogie'? and 4slide blocks pivoted to the upper 'ends'of the said: two guideways; said ball-joint comprising a v socket member slidable upon one of said guideways and a ball, infsaid socket, and lslidable'upoen the other guideway; and meansfor controlling the movement of said ball joint'due to vlateral displacement of tloeboiler with regard to the bogie to maintain a denite proportion between the distances of said ball joint from the middle plane of theboiler and the bugie; ysaid proportion being substantially 1:1. v

7,; 11n* a Mallet locomotive of the "type wherein the :boiler is supportedupon affront bogie and rear frame, the combination ofi abfoiler; a front bogie; means for supporting said"boi1er onsaid front bogie, said means comprising a guideway fixed to the under side of 'the boiler; a guideway upon the bogie; and a ball joint located between I said two guideways; said ball-joint comprising ak socket member slidable upon one of'said guideways and a balLin said socket, and slidable upon the other guideway; and means .for controlling the movement of said ball jointdue to'lateal displacement of the boiler with` regard* tothe bogie to maintain a definite proportion between the distances of said ball joint from 'the'middle plane of the boiler and the bogie, said means-for controlling the movement of Vtheball joint'cor'ni prising levers, each pivotedat an intermediate point along the length thereof to the ball Ajoint and operatively connected at the ends thereof to the boiler and the bogie respectively, the Araltio of the eiective arm lengths of the levers bein g different'. ff

' KARL ROTHLER. 

